18 found

Tech Notes

An Introduction to Single Screw Extrusion

Extrusion is a process used for creating a product (an extrudate) by forcing a material through a die or an orifice to form a shape, or alternatively an extruder is used to produce semi-finished or finished products.

ATP White Paper

The controlling factor in all polymer conversion processes is the materials rheological behavior. Check out this recent white paper in conjunction with EMC Electrical Mechanical Controls and Applied Polymer Technologies (APT) and learn how rheological measurements can detect the most discrete changes in structural properties.

Closed Loop Pressure Control for the Extrusion Process

Extrusion is a continuous process and successful economic production depends on maintaining stable output and melt quality at an accurately controlled rate. Current screw design technology, the use of DC drives, computerized controllers and raw material testing help to deliver the melt to the extrusion die at relatively constant temperature, pressure and viscosity.

Coping with Transducer-Crippling Pressure Spikes

After investigating these spikes, we developed a laboratory method for determining the magnitude of the actual pressure spike that caused a specific field failure. The method shows that pressure spikes many times that of nominal system pressure can occur in a system.

Detecting Polymers in Material Products

It can be very difficult, if not impossible, to achieve complete indentification of most polymer products. However, in most cases, this is usually not needed; what is needed is the separation, or identification, of numerous molding materials whose identity has been lost, or an indication of the type of material used to create a component.

Dynisco Pressure Transducers Relay Vital Information for Closed Loop Control

One of the fastest growing areas for the use of pressure measurement instrumentation is in the co-extrusion of multi layer barrier structures. Many leading co-extrusion design and manufacturing firms, such as the Cloeren Company, engineer melt pressure transducers into their systems for closed loop process control.

Gage vs. Absolute vs. Sealed Pressure

By design, pressure transducers are available to measure gage, absolute or sealed pressure. The most common reference is atmospheric pressure and the units are designated at PSIG. In this case the measuring device is referred to as a Gage Pressure Transducer.

Guardian PL'c' (Performance Level 'c') Safety Notes

Determining functional safety is complicated and minimally involves an assessment of the probability of failure, an assessment of impact resulting from failure, and a path to address a failure should it occur. While the supplier evaluates and classifies the safety assessment of his equipment, the user decides, selects, installs, and tests the type of equipment that is needed.

Guide to Pressure Transducer Selection

The purpose of this article is to provide some guidelines for helping a transducer user detect atypical conditions and compensate for them through the proper selection and application of the transducer.

Key Violation in LabKars Software

The following instructions will resolve the key violation error that appears in Labkars software, which is used to control our LCR7000 series capillary rheometers

LaVA Suite Requirements

The LaVA Suite software for the new LMI5000 series has the look and feel of applications for the latest PCs or mobile devices. Screen layout and menu navigation is immediately intuitive to lab personnel of every skill level.

LMI Weights and Combinations

No longer are large, heavy weights needed to achieve all of the ASTM D1238 testing conditions. Operators will now be able to stack combinations of smaller, easier to handle weights to attain the desired overall weight. With the introduction of these new weights, we are also introducing a new, easier to understand part number system. Please use this document as a guide to the new part numbers as well as for suggestions on how to achieve the ASTM D1238 weight values.

Melt Pressure Measurement: Environmental Effects

The Need For Pressure Measurement in Extrusion In order to maintain the dimensional stability necessary to produce extruded products that meet todays precise quality and tolerance specifications, it is necessary to keep both the output rate and the melt condition constant (1,2). Although it is not possible to measure these quantities continuously, closely related variables such as melt temperature, and constant melt pressure at the die, the output rate can be considered constant.

Melt Processing of Thermoplastics for Extrusion and Injection Molding

Extrusion and injection molding are the most important conversion techniques used by the thermoplastics processing industry, Certain factors need to be considered before a thermoplastics material is processed, regardless of whether it is injection molding or extrusion molding that is used.

Oil Fill Offset

An oil‐filled sensor has the advantage of being non‐toxic and therefore compliant for many food, medical or other critical applications. A disadvantage of an oil‐filled system is that the organic oil fill can degrade over time at high temperatures.

Operating Standards and Records

The overall performance of an extrusion line is strongly dependent upon selection of processing conditions and proper maintenance of extrusion hardware. Management should not expect to achieve a high-quality product at good production rates if extrusion equipment is not well maintained or if operating conditions are not well defined.

The Do's and Don'ts of Pressure Transducers

When specifying a pressure transducer for a process measurement, a number of items have to be considered. Some of the more important ones are discussed in terms of the transducer itself as well as the overall measuring system. This information is user-oriented and serves as a practical guide in the selection and application of strain gage pressure transducers.

The Importance of Monitoring Extrusion Stability

It has long been known that pressure instability for polymer melt entering the die usually results directly in ouput variation. Instrumentation used in these early studies was too delicate and expensive to be practical for routine commercial use. An excellent article written by B. H. Maddock, covering some of his early studies is title “Measurement and Analysis of Extruder Stability.”